The present invention relates to vehicle steering arrangements and in particular to such arrangements for vehicles with retractable wheels.
Front wheels which are arranged to be steered and retracted for an amphibious vehicle are shown in our copending International Patent Application No PCT/GB04/001422. In that arrangement the wheels are retracted through nearly 90° so as to enable good clearance of the water; but also because there is plenty of room for accommodating the wheels. At the end of each steering arm articulatedly connected between the arm and an upright member on which the road wheel is mounted is a link, which is also articulated to the upright member. When the road wheel is protracted, the link is mostly horizontal and acts as an extension to the steering arm so as to steer the road wheel. When the road wheel is retracted, the link is mostly upright so that any movement of the steering arm such as occurs when steering the vehicle in water by directing a pump jet at the rear is not, or is largely not transmitted to the pivotally mounted upright member.
Therefore the retracted road wheels are not or are largely not caused to pivot. Any movement of the road wheels can be accommodated within pockets provided for accommodating most of the road wheels. In a case where it is not possible to rotate a steered suspension for a pair of road wheels to an angle as much as PCT/GB04/001422 indicates, any linkage as shown in that patent application will cause the road wheels to pivot when the vehicle is steered in water. To allow for this movement of the road wheels, the wheel pockets would have to be excessively large. This would result in loss of body space and could cause problems when the vehicle tramped on water, as the clearance around the wheels could allow water to be scooped up, causing excess spray and impeding forward progress.
Where it is necessary to retract the road wheels further so that the link at each end of the steering which connects to the upright member is, at full retraction, beyond vertical, that is, the link is angled inwards at, for instance, 20° to the vertical, then the same problem occurs as when the link is angled outwards, as described in the paragraph above.